Sun Screen

Jun 9, 2015

By Trevor Shewfelt, Pharmacist at the Dauphin Clinic Pharmacy

Last weekend my parents came out for a visit. At supper, my mom asked Eric what he did in school that day. Eric said he had a science class in the afternoon. Eric was obviously excited and said, You know science. Like how stuff blows up! My dad told Eric that really only a very small part of science was about blowing stuff up. And my dad should know. He is a retired physicist who worked on the properties of metal components in nuclear reactors. I told Eric to ask his grandfather how he experimented on zirconium pressure tubes. My dad got a big grin on his face and said, Well, we blew them up!

Blowing stuff up may be a very small part of science, but it sure is fun. It is like sunshine. Swimming, fishing, bike riding and sitting on the beach are fantastic summer activities, but they sure are more fun with sunshine! Just like explosions, sunshine can be dangerous as well. Too much sun can damage your skin. And that damage can add up. Sun exposure can lead to serious problems like skin cancer.

The sun emits radiation across the entire electromagnetic spectrum, from radio waves to X-rays. The part of the spectrum we are interested in for skin damage are the Ultra-violet wavelengths. There are 2 types of UV radiation we talk about with skin damage, UVA and UVB. Sun burn is most often caused by UVB. UVA & UVB can both cause premature skin aging, and skin cancer.

Sun exposure is a factor in the development of three types of skin cancer. Basal cell carcinoma is caused by the exposure to UV radiation and is the most common type of skin cancer. Basal cell carcinoma often affects fair-skinned people with blond or red hair who sun burn easily. Basal cell carcinoma is usually very easy to treat. Squamous cell carcinoma, the second most common form of skin cancer, is caused by repeated exposure to the sun over a long period of time. It can be very successfully treated if it is identified early. Malignant melanoma is a less common skin cancer. We believe sun exposure is one of its causes. If malignant melanoma is found early, it has a high cure rate. However, if it is not caught early, it can spread to the blood stream and in the worst cases, it can cause death. If sunscreen is used properly, it has been shown to reduce the number of cases of squamous cell carcinoma, and it may help reduce the risk of malignant melanoma. There is debate about how well sun screens protect against basal cell carcinoma.

The Food and Drug Administration in the US started to require changes in the labeling of sunscreens in 2012. Health Canada followed suit in July 2013. Sunscreens can no longer be labeled Sunblock, and they cant claim immediate protection upon application. The FDA thinks sunblock implies too much protection. If the sunscreen protects against both UVA and UVB and has an SPF of 15 or greater, it can be labelled as Broad Spectrum. The FDA also wont allow a sunscreen to claim an SPF of greater than 50 as they feel there is no evidence that numbers above 50 have any real meaning. Sunscreens arent to be labelled water proof or sweat proof. They are only able to say they are water resistant. The label must state how long they are water resistant for. The two labeling options are water resistant for 40 minutes or water resistant for 80 minutes.

Sunscreen shouldnt be the only defense used to prevent skin cancer. Here are some practical suggestions.

  • Avoid the sun when it is most intense. This is generally between the hours of 11 am and 4 pm.
  • Seek the shade when you are outside for a long period of time
  • Wear a hat with a wide brim and long-sleeved shirt.

There is lots more to science than blowing things up. Back in 1989, physicists at CERN on the French-Swiss border invented the World Wide Web. They did this to move information about the experiments they were doing around easier. But the web really was only a side project. CERN is now the home of the large Hadron Collider in which they smash subatomic particles together at nearly the speed of light. When the colliding particles explode, the physicists learn more about the very natural of the universe. Maybe Eric is right. Maybe all of science really is about blowing stuff up.

As always if you have any questions or concerns about these or other products, ask your pharmacist.

The information in this article is intended as a helpful guide only. It is not intended to be used as a substitute for professional advice. If you have any questions about your medications and what is right for you see your doctor, pharmacist or other health care professional.

We now have this and most other articles published in the Parkland Shopper on our Website. Please visit us at

Canadian Dermatology Association- Sun Safety -

CERN The birthplace of the Web -

Large Hadron Collider -


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